For example, from a viewpoint of copyright protection or the like, there is a system for managing a deadline about permission/non-permission of reproduction with respect to contents recorded on a media.
That is, for example, the reproduction of the contents is permitted within a predetermined period and, after the elapse of such a period, the reproduction is not permitted. Thus, monitoring of the contents by the user is enabled within the predetermined period and, after the passing of the deadline, for example, the user is instructed to newly purchase the contents at a normal price.
As a system for enabling the contents to be monitored within the predetermined period and, there after, letting the contents be purchased again as mentioned above, for example, there is a system using the following system.
First, the encrypted contents is recorded as a media as mentioned above. A key for decrypting the encrypted contents is given for a predetermined period, thereby enabling the contents to be monitored for the predetermined period.
In such a system, when the contents recorded in the media as mentioned above is reproduced, for example, the user accesses a predetermined server with the media loaded into a reproducing apparatus. The server side returns key information to decrypt the encryption in response to the access for the predetermined period, thereby enabling the contents to be reproduced on the reproducing apparatus side.
In this instance, to permit the reproduction of the contents for as certain predetermined period as mentioned above, deadline information of each contents of each media has to be managed on the server side. That is, a mechanism which can distinguish, among the contents whose reproduction is required of which contents has passed the deadline and which contents is not is necessary.
For this purpose, according to the conventional technique, first, at the time of the first reproducing request of the contents, the user is instructed to set and register predetermined information (name, date of birth, address, telephone number, occupation, etc.) into the server and a correspondence between the contents and its deadline is obtained according to the registration information on the server side.
Corresponding to the completion of the registration, first, the key for decryption is returned to the reproducing apparatus side, thereby permitting the reproduction of the contents. Further, in this instance, reference time for management of the contents deadline is set into the reproducing apparatus side from the server side and, after that, each time the reproducing request of the contents is issued, the deadline of the contents is monitored according to such reference time set into the reproducing apparatus side.
According to the conventional technique, as mentioned above, by making the registration information such as personal information or the like of the user set on the server side at the time of the first reproducing request, the correspondence between the contents recorded in the media held by the user and the deadline information corresponding to such contents is obtained.
In addition to it, by setting the reference time to the reproducing apparatus side at the time of the first reproducing request, the deadline of the contents is managed after that on the basis of the reference time which is presented by the reproducing apparatus side at the time of accessing.
However, such a conventional technique has the following problems.
First, in the conventional technique as mentioned above, it is indispensable to accurately maintain the reference time which is set by the server side on the reproducing apparatus side. For this purpose, some clock function has to be provided for the reproducing apparatus side. However, it is technically difficult to accurately maintain and manage such a clock function and such a difficulty influences whether or not such a system can be accomplished.
Also in this instance, such a clock on the reproducing apparatus side can be often arbitrarily adjusted by the user. There is, consequently, a fear that the reference time set by the server is changed and it also influences whether or not such a system can be accomplished.
In the conventional technique as mentioned above, to allow the user to receive services, first, the personal information (name, date of birth, address, telephone number, occupation, etc.) for authentication is registered into the server side.
This causes, for example, the following possibility when there is a defect in an information management system of the side of administrating the server; that is, a possibility that such user's personal information leaks to the outside and it develops to a social problem.
Since the user has to register the personal information or the like in order that the reproduction deadline of the contents is managed as mentioned above, the following inconvenience occurs.
That is, for example, assuming that there is a reproducing apparatus in which the user registration has already been made, and if the user buys a new reproducing apparatus aside from the existing reproducing apparatus and intends to receive services by the reproducing apparatus after the purchase, in spite of the fact that the user registration has already been made once, the user registration has to be performed again to the server with respect to the new reproducing apparatus.
That is, according to the foregoing conventional technique as mentioned above, when the user intends to receive the services by using another reproducing apparatus, the above problem forces the user to have troublesomeness of the new registration and he is heavily burdened.
Since such troublesomeness is compelled, in the conventional technique as mentioned above, it is difficult to freely access the server apparatus and receive the services after exchanging the reproducing apparatus.
Further, according to such a conventional technique, since the deadline of each contents is managed according to the reference time set into the reproducing apparatus side as mentioned above, for example, in the case where the same media is loaded into another reproducing apparatus and a reproducing request is newly made to the server side, new reference time can be set in such a reproducing apparatus.
That is, there is such a problem that since the reproduction deadline of the contents can be arbitrarily extended, the deadline management of the contents is not completed in dependence on the conventional system.
Counter measuring the problems of such a conventional technique, the invention shown in JP-A-2002-8115 is constructed in such a manner that prepaid information is preliminarily stored into the media and, upon downloading of the contents, the server side executes a charging process on the basis of the prepaid information.
According to the technique of JP-A-2002-8115, ID information peculiar to each media and prepaid money amount information are recorded as prepaid information.
According to the technique, since each media can be identified by the peculiar ID information, in this case, when each user is identified on the server side, the operation for allowing the user to set the registration information such as personal information and the like as mentioned above is unnecessary.
Since the contents of a money amount over the prepaid money amount cannot be downloaded, the copyright can be effectively protected.
However, since the technique disclosed in JP-A-2002-8115 is made on the assumption that the contents is downloaded to the blank media, the reproduction deadline of the contents which has previously been recorded in the media as mentioned in the above conventional technique cannot be managed.